I'm just making this thread to ask if the thickness of bar matters. Recently a new gym has opened near me and has 4 Olympic platforms, but the bars are 30mm but they still have spinning sleeves which is good. Should I train with these bars? Or find somewhere else to train? Note: the bars are Jordan barbells.

It will really matter if you plan on competing. The transition will be rough!
Also, hook gripping will be hard and it definitely will be a disadvantage when trying to maximize on your snatch and clean & jerk.

While it is not ideal, it is doable.

Also, if they don't spin well and you find they are locking up, it can cause a lot of problems in your wrists, elbows, and shoulders. Just a thought!